Chapter 7: Adventures in Bodybuilding

This chapter compared animals' bodies to a house being built from information contained in bricks rather than the builder...this concept was initially hard to grasp, but then Shubin stated that different parts work together to make a greater whole; dividing labor between parts. He stated that most of life's history is that of single-celled creatures...comparing Earth's timeline with a twelve-month calendar (only single-celled creatures present until June and then humans appear on Decemter 31st). The first creatures of many cells occur during the Precambrian, populating the sea 600 million years ago, and with these bodies bring the first trackways, revealing some were able to move in relatively complicated motions. To better understand how our bodies work, Shubin stated the difference between organs rests in the way cells and materials are arranged in tissues; with molecules that make cellular arrangements possible also making formation of bodies possible (these molecules make our bones). These moleules determine the mechanical differences among bone, teeth and cartilage based on their ratios of various materials. It is so cool how one is able to tell which molecules and where they come from just by their formation under a microscope! Then Shubin even went on to state that all animals have molecules that lie between cells (more specifically collagen and proteoglycans). These molecules are very interesting, especially since collagen is the most common protein in our body (nearly 90% of body's protein by weight!). Cells in organs have to able to stick to one another and to talk to each other; with molecular rivets to help them stick together (selective rivets enable cells to organize our bodies in a fundamental way) and allowing cells to communicate by using "words" written as molecules that move from cell to cell (send molecules back and forth). Although I always felt our body is extremely complicated and way more advanced than single-celled organisms, I was shocked once Shubin stated our bodies have many of the same things as placozoans (literally blobs!) and sponges: they have cells with divisions of labor, cells that can communicate, and an array of cells that functions as a single individual (simple versions of our bodies!). Further study of single-celled microbes proved the potential to build bodies came before bodies actually appeared! It is believed that predation could have brought about bodies (microbes began to eat one another), and that bodies came when they did because the environment was not ready before-hand (levels of oxygen too low to support larger organisms). This chapter further enlightened me on our body and the history of where it came from...I am excited to find out what else Shubin has to teach me!